Paul Apurba, Padmapriya Ponnan, Natarajan Vasant
Department of Physics, Indian Institute of Science, Bangalore, India.
Department of Physics, Indian Institute of Science, Bangalore, India.
Biomed J. 2017 Apr;40(2):101-105. doi: 10.1016/j.bj.2016.10.001. Epub 2017 May 5.
In previous work studying the properties of red blood cells (RBCs) held in an optical tweezers trap, we observed an increase in the spectrum of Brownian fluctuations for RBCs from a Plasmodium falciparum culture-due to increased rigidity of the cells-compared to normal RBCs. We wanted to extend the study to patient samples, since the earlier work was done with cultures grown in the lab.
Individual RBCs were held in an optical-tweezers trap. Its position fluctuations were measured and the power spectrum determined. The corner frequency (f) of the spectrum gave a quantitative measurement of the spectrum.
The value of f was 25 Hz for normal cells, which increased to 29 Hz for infected cells-both for P. falciparum and Plasmodium vivax infections.
The technique of measuring f can be used as a screening tool for malaria in patients with fever, since RBCs not carrying the parasite will also show the change due to the bystander effect, irrespective of whether it is caused by P. falciparum or P. vivax.
在之前一项研究光学镊子捕获的红细胞（RBC）特性的工作中，我们观察到，与正常红细胞相比，来自恶性疟原虫培养物中的红细胞布朗运动波动频谱增加，这是由于细胞刚性增加所致。我们希望将该研究扩展至患者样本，因为早期工作是使用实验室培养物完成的。
将单个红细胞置于光学镊子捕获装置中。测量其位置波动并确定功率谱。频谱的拐角频率（f）给出了频谱的定量测量值。
正常细胞的f值为25赫兹，对于感染了恶性疟原虫和间日疟原虫的细胞，该值增至29赫兹。
测量f的技术可作为发热患者疟疾的筛查工具，因为未携带寄生虫的红细胞也会因旁观者效应而出现变化，无论这种效应是由恶性疟原虫还是间日疟原虫引起的。
